Means for tuning a radio receiver



Original Filed Sept. 2, 1950 Feb. 16, 1960 B. A. scHwARz ETAL v2,924,980

MEANS FOR TUNING A RADIO RECEIVER 4 9 sheets-sheet 1 "F il twentors M yCttornegs Feb. 16, 1960 a. A. scHwARz ET AL 2,924,980

MENS FOR TUNING A RADIO RECEIVER Original Filed Sept. 2, 1950 9Sheets-Sheet 2 Bnvcntors Feb l5, 1.960 B. A. SCHWARZ ETAL 2,924,980

MEANS Eon TUNING A RADIO RECEIVER Feb. 16, 1960 B. A.\.scHwARz ET AL2,924,980

MEANS FOR TUNING A RADIO RECEIVER Feb. 16, 1960 B. A. scHwARz ETAL MEANSFOR TUNING A RADIO RECEIVER original Filed sept. 2, 195o 9 Sheets-Sheet5 Bu @j M Feb. 16, 1960 l B. Al SCHWARZ ET AL 2,924,980

MEANS F OR TUNING A RADIO RECEIVER 9 Sheets-Sheet 6 Original Filed Sept.2, 1950 Bnventors ffm/@fav A WWW v Z A Nw fx MH Feb. 16, 1960 B. A.SCHWARZ ETAL 2,924,980

MEANS FOR TUNING A RADIo RECEIVER Original Flevd Sept. 2, 1950 9Sheets-Sheet 7 Feb. 16, 1960 B. A. SCHWARZ ET AL 2,924,980

MEANS EoR TUNING A RADIO RECEIVER 9 Sheets-Sheet 8 Original Filed Sept.2, 1950 :inventors 520% y Gttornegs Feb. 16, 1960 B. A. SCHWARZ ETAL@924,980

MEANS FOR TUNING A RADIO RECEIVER Original Filed Sept. 2, 1950 9Sheets-Sheet 9 y l s United States MEANS ron TUNING A nAnIo RECEIVERBertram A. Schwarz and Manfred G. Wright, Kokomo,

Ind., assignors to Generai Motors Corporation, Detroit, Mich., acorporation of Delaware Continuation of application Serial No. 183,069,September 2, 1950. This application February 4, 1953, Serial No. 713,124

19 Claims. (Cl. 74,-1052) .filed Dec. 2, 1948.

Many of the commercially available radio receivers that are currently onthe market are equipped with push button tuning means so that thereceiver may be quickly brought into tune for a previously adjustedstation. These tuners are merely mechanical indexing means that adjustthe parts to predetermined locations to tune the receiver.

There are also on the market some receivers that are provided with someform of driving means to cause the tuner to sweep or scan the band andsome means responsive to incoming signal strength to cause the drivingmeans to become inoperative if a signal of suiiicient strength isreceived. This general type of tuner control is described and claimed ina copending Patent No. 2,550,430 in the names of Bertram A. Schwarz andI ames H. Guyton, filed July 5, 1947, entitled Electronically ControlledTuner. The scanning drive in that case was described as a reversiblemotor which was controlled by the circuit disclosed.

It is an object of our invention to provide a novel driving means forcausing the tuning means to sweep over its ambit and scan the band.

It is a still further object of our invention to provide a combinationspring and solenoid drive for tuning means.

It is a still further object of our invention to provide arresting andspeed control means for the spring and solenoid drive.

It is a still further object of our invention to provide both a manualand an automatic drive for the tuner.

It is a still further object of our invention to provide a differentialmanual drive for the tuning means.

It is a still further object of ourinvention to provide a differentialmanual drive for the tuning means which will not be injured at the endof travel of the tuner by continued rotationof the manual means.

With these and other objects in view which will become more `apparent;as the specification proceeds, our invention may be better understood byreference to the following specification and claims and theillustrations in the accompanying drawings in which:

Figure 1 is a front elevation of the control panel of a radio receiverembodying our invention.

Figure 2 is a top plan view of the tuner -with the casing removed takenon line 2-2 of Figure 1.

Figure 3 is a side elevation of the same taken on line 3-3 of Figure 2.

Figure 4 is a horizontal sectional view taken on the line 4-4 of Figure3.

2,924,980 Patented Feb. 16, 1960 Figure 5 is a vertical sectional viewshowing the driving gears and taken on the line 5-5 of Figure 4.

Figure 6 is a sectional view showing a part of the driving gears `andthe governor taken on line 6-6 of Figure 4.

Figure 7 is a 'partial bottom plan view taken on line 7-7 of Figure 3.

Figure 8 is a partial top plan view showing the reverse side of themechanism shown in Figure 7.

Figure `9 is a perspective view of the planetary gear carriage. l

Figure 10 is a circuit diagram showing the electrical control circuitfor the form of tuner shown in Figures 1-9.

Figure 11 is a top plan view of a modilied form of tuner embodying ourinvention.

Figure 12 is a transverse vertical sectional view taken on the line12-12 of Figure 11.

Figure 13 is a longitudinal vertical sectional view taken on the line13-13 of Figure l1.

Figure 14 is a perspective view showing the sector gear drive for thisform of our invention.

Figure 15 is a horizontal sectional view taken on the line 15-15 ofFigure 13.

Figure 16 is a top plan view similar to Figure 11 showing the parts inthe opposite extreme position of movement; and

Figure 17 is a circuit diagram showing the electrical circuit for thismodilied form of tuner.

Referring now to that form of the invention shown in Figures l through10 inclusive, it is conventional practice to tune a plurality ofresonant circuits of a receiver either by varying the capacity of thesecircuits through the use of a variable condenser which is connected in aresonant circuit with a tixed inductance or to vary an inductance whichis connected across a fixed condenser of a circuit. The latter type oftuning is shown here for illustrative purposes only as our invention iscapable of use with either form.

The variable inductance or permeability tuning is accomplished by usinga plurality of tuning coils 2 mounted in spaced parallel relation whichare connected into the various resonant circuits of the receiver andthen movably mounting a plurality of compressed comminuted iron cores 4so that they may be simultaneously inserted into the coils to varyingdistances and thus change the inductance of each to tune the circuitsdesired. The cores 4 are adjustably mounted on a transverse bar 6 byhaving -threaded ends 8 in engagement with threaded openingsin the bar.This is primarily for alignment purposes and once adjusted are veryseldom independently moved. Thus as the bar travels back and forth onthe tuner the cores 4 will be plunged into the coils 2 and the settuned.

The transverse bar 6 s `supported on a movable carriage 10 having, anupturned ange 12 at the front to which the bar is rigidly aliixed. Amain frame consisting of a base 14 and two integral upturned endportions 16 and 18 has a plurality of tie rods 20 extendinglongitudinally between the end portions to give the structure rigidity.The upturned carriage flange 12 has an opening therethrough throughwhich one of the rods 20 projects and an additional flange 22 at therear of the carriage also has an opening therein for the same rod; thusthe rod acts as a track or trolley for the carriage as it moves back andforth and supports the same. Mounted on the base 14 are a pair of spacedsupporting plates 24 and 26. These plates are parallel and in the mainsupport the various driving gears. The lfront casing Wall has Yanopening 28 therein in which the dial 30 is supported and through whichthe .pointer 32 projects. The pointer is pivotally mounted at 34 on apivoted link 36 carried by plate 26. l

An additional supporting plate 38 is mounted on plate 26 byscrews'40and--extends out over the edge of the latter as shown inFigurefZ. Two ears v42 on this over hanging portion are bent ,down3 andiprovide aligned openings to rotatablysupport. a manually operated shaft44 driven by knob 46 on the control panel, said shaft carrying a worm48. A bell crank 50-ispivotally mounted at 52 on this plate 38, theshorter arm of said .crank being pivotally connected to the pointer at54 and the longer end-pivotally connected to alink 56 in turn con nectedto thefcarriage -at 58. Thusasthelcarriage moves longitudinally of thetuner assembly the link 56 will iny turn rotate the bell crank tovmovethepointer and due to the geometry of. the systemthe pointer will. havesubstantially straight-line movement across the dial since the pivot34moves back `and forth as the pointer'32 moves across the dial.

The movement of the carriagebackandforth to move the cores 4 into andout of the associated coils vto tune the receiver is accomplishedeither-by manual gear drive or automatically by a spring 60which isunder tension and tends to move the carriage in one direction and asolenoid 62 which, when energized, movesthe carriage in the oppositedirection and cocks or loads the spring. It is obvious that the movementcaused by thesolenoid is rapid and consumes only a short period of time.The vspring drive, however, isl loaded through amovable gear train andis thus slowed down to a proper scanning speed. The manually operableknob '46 must also in some manner provide engagement to the geartrainthrough its worm 48 so that the knob can be used to move thecarriage and tune the set regardless of the position of the apparatus.

Referring now more specifically to Figure 5, it will be seen that thetwo spaced plates 24 and 26 carry in vertically aligned openings arotatableshaft 64 upon which are mounted a plurality of spur gears 66and 68 and a pinion 70. Spur gear 66 acts as aiworm wheel and engagesthe threads of the worm 48 to turn therewith. It may be rigidly securedto the shaft 64. Spur gear 68 iS rigidly secured to pinion 70 and Aisadapted to'turn therewith, both however, being free to rotate on theshaft 64.

A pivotally movable frame planetary carriagerin which a multiplicityofgears and transfer shafts are. mounted is used in conjunction with thegears already mentioned to transfer motion from either the manual orpower drive to the ycarriage supporting the tuning cores. This.rotatable carriage is best shown in Figure 9 and consists of two spiders72 and 74 which are held inA spaced relation to each other by spacingbolts 76 and 78. They are both of irregular configuration and aresoshaped as toprovide a plurality of'spaced aligned openings in which tovertically support a plurality of shafts as well as tofsimul- 'taneouslyprovide extending arms or connections to other portions of theapparatus. At opposite points these two spiders '72 and 74 have beendepressed toward each other adjacent aligned openings as at 80 and 82andthese openings are adapted to iit over projecting opposite ends of theshaft 64 which provides a pivot for the spider assembly. A second pairof aligned openings 84 support in a vertical position shaft 86.

A'disc 83 is ixedly mounted on theupper end of the shaft 86 by a pin 85or other suitable securing means. The shaft 86 has'a section of largerdiameter 87 which provides a shoulder for supporting gear 88 which isnot keyed on shaft 86. A'bowed'spring 89 tends 'to force the gear 88against-the shoulder by exerting axial force on the upper face of thegear and `the tiredV disc 83. Gear 8S then will normallyfturn with'shaft86 `but may yslip thereon, provdinga friction drive to protect theparts if driving force is continued after the tuningmeans reaches oneextremity.` y

A-plate 91'is mounted on vthe-lower end ofthe shaft 186 through avpressed fit connection. This plate has an extending hub section 93 onwhich gear 90 is mounted for rotation. A ratchet wheel 95 is alsorigidly connected to the shaft 86 and holds the gear 90 between itsupper surface and the plate 91, the gear being freely rotatable lon itsmounting. A pawl-97 `is-pivotally mounted on the gear .90 and maintainedin contact vwith the teeth 99 of the ratchet Wheel 95 by an arcuatespring member 101 having one end secured' to the lower surface of theratchet Wheel. "(See Figure'7.) Thus the gear 90 islocked to the shaftthrough the ratchet and pawl for driving in one direction but is freelyrotatable thereon for rotation in the opposite direction. This is vtoprovide for the rapid `cooking movement by the solenoid.

Spider 72 has .a projecting arm 9.2 `to which one end of the drivespring 60 is secured, the opposite end of said spring being retained inend wall 18 of the casing. Thus ,spring 60 tends to rotatethespiderassembly counterclockwise as shown in Figure'9 about the axisof shaft `64.at bearings 80 and 82. Spider arm 74 also has'a projectingear 94 to which is connected a link v96, the opposite end of which ispivotally connected to the main carriage 10. Thus -as the spiderassembly rotates around the axis of the shaft 64 it causes the carriage10 to move longitudinally of the .tuner and tune the receiver.

To continue with the driving gear train and referring now morespecifically to Figure 6, the two plates 24 and 26 support aplurality ofvertical spaced shafts 98, 100 and 102, shaft 98 having mountedthereonyspur gear 104 and pinion 106, shaft 100 carrying in like mannerspur gear 108-and pinion 110 and lastly, shaft -102 carrying transferpinion .112. The pinion 106 is adapted to be engaged by spur gear 68mounted on the first described shaft 64. The .gear train then, isevident from pinion 106 which rotates with spur gear 104 to drive themating pinion 110 which rotates in like manner rigidly with spur gear'108, the last named gear mating with and driving pinion 112 on shaft102. This is a straight reduction gearing by which the governor isdriven from the original train, the governor in this instance being arectangular liat plate 114 having slots therein and a bowed out sectionto support it on shaft 102 so that it acts as a friction or air governoras that shaft rotates. It is, vof course, rigidly secured to its shaft.Any other similar type of governor may of course be substituted.

It will thus be evident that the spring "60 tending to rotate the spidercarriage counterclockwise as shown in Figure 9, tends to move the maincarriage 10 toward the front of the receiver or to pullout the tuningcores to their extreme position from their association with the coils 2.y Some means must .therefore be provided to move the mechanism to theopposite extreme position or cock the spring so that the latter mayagain bias itto return it to the front. This means, as previouslystated, is a solenoid coil 62 which is mounted on the back of theVertical wall 18 and which has a movablevcore 116 to ywhich is pivotallymounted one end of a lever 118, the opposite end of which is pivotallyconnected to an additional extension on the spider 72. Thisinterconnecting lever 118 has a fixed pivot 122 on the under side ofplate 24. Thus as the solenoid sucks in its core and therefore turns thelever-118 clockwise around the pivot 122, asshown in Figure 7, thespider carriage will be turned in a counterclockwise direction, the pawlslipping over the ratchet wheel, to again tension the drive spring-60and start the carriage slowly rotating to withdraw the core 116 from thesolenoid and scan the band in that direction.

Switching means. must therefore be providedto Venergize the solenoid atthe end of travel in one direction and Ytodeenergire it whenit hasreturned the carriage to the other extreme of travel. This switchingmeans incorpor- 'ates a plurality of switch arms 124, 126 and 128 whichare mounted between insulating wafers'130,whichform "a block, the wholebeing supportedon an upstanding arm 132 from the base 14. A snap-overspring actuating arm assembly 134 engages the outer en'd of the movableswitch contact arm 126 to atemately move it from one 'side to the other.This arm 134 `also projects out into the path of two upstanding ears 136and 138, which are mounted on the carriage and are adapted to engage andcause snap-over of switchv arm 134 at opposite ends of travel.

In order to tune the setmanually, we have provided a differential manualdrive so that the gear train may be used for the automatic drive, butwhen that is locked the manual knob may be used to move the tuningcarriage. During automatic tuning the worm 48 is of course stationary,and since worm Wheel 66 is in mesh therewith, it cannot rotate. Gearwheel 66, therefore, acts `as a reaction point and the spider carriagerotates about the axis of the gear 66. As the spider carriage rotatesabout this axis, caused by the spring, the gear 88, which is in meshwith the periphery of 66, will rotate and this will drive the gear trainto provide the load, and also rotate the governor. When driven by thesolenoid rapidly the gear 88 rotates the shaft 86 but the pawl slipsover the ratchet wheel and gear 90 is not driven. However, if thegovernor is locked by engagement with one of the stopping arms, then thegear 88 cannot rotate about its own axis and rotation of the manual knob48 and wheel 66 will cause the carriage to have planetary motion or walkas a whole around the periphery of the gear wheel 66. Thus either wheel66 lis locked for automatic movement or wheel 88 is locked for manual.

If the manual knob 46 is rotated to cause the tuning means to move toone extremity of travel and then continued force applied which mightcause parts to be broken, such action will overcome the friction lock ongear 88 and it will rotate an shaft 86 thus protecting the gearing fromdamage.

As stated previously, the spring provides a steadily constant drive inone direction to move the carriage so that the comminuted cores aremoved out of their associated coils. The required slow movement isprovided by the load of the gear train and the air resistance of thegovernor. However, the receiver must be controlled and stopped atcertain points depending upon the existence of wanted signals and inorder to properly control, index and stop the same, there are provided apair of relays 140 and 142 which are mounted upon the base and each ofwhich is adapted to actuate an armature to which is rigidly securedangularly shaped stop rods 144 and 146. These rods project to a positionadjacent the governor 114 but are movable to position out of contacttherewith.

These two relays have different functions to perform. By reference toFigure 4, it will be seen that when relay 140 is deenergized, the arm144 will move to stop the governor. This locks the mechanism when theset is deenergized and the main switch is off. This relay also has alock-incontact 145 insulated from the armature which closes the hold-incircuit once the set is turned on and the push button switch 148 hasbeen pushed. The second relay 142 operates in the opposite sense. Thatis, it acts as a stop for the governor when the relay coil is energizedand the armature drawn in against the spring pressure. This armaturealso carries an insulated switching contact, cooperating with contact147.

A circuit diagram of the various electrical connections for the systemis shown in Figure 10. A battery 149 is provided which is connected tomain switch 151, and thence to conductor 153. The latter extends to oneterminal of the solenoid coil 62 and to one terminal of the relay coil140. The opposite terminal of the solenoid operator coil 62 is connecteddirectly to movablev switch arm 126, which is snapped over center byarms 136 and 138 to reverse the direction of carriage drive. Theopposite terminal of the relay 140 is connected to line 155,.whichextends to grounding switch 148. Holding contact 145'is likewiseconnected to line 155.

The control circuit for indexing relay 142 is similar' to thosedisclosed in the co-pending Schwarz and Guyton Patent No. 2,550,430,previously mentioned, and will only be briey describedhere as it formsno part of the present invention. One of the resonant coupling circuits157 of a radio receiver is shown connected to the rectifier tube 159. Aconductive line 161 extends from this coupling circuit to resistor 163and thence to grid 165 of tube 167. The cathode 169 of this latter tubeis connected through line 171 to a variable tap 173 on resistor 175 inthe cathode circuit of tube 159. The plate 177 of tube 167 is connectedto condenser-179 and thence through'two resistances 181 and 183 inseries to the positive potential of a B battery, as indicated by B|.Conductive line 185 extends from the plate circuit to the contact 147 ofrelay 142. Movable armature 146', which is in realitya physical part ofarm 146, is adapted to contact 147 and is electrically connected to line187, which extends to a point intermediate condenser 179 and resistor181, to the grid 189 of the tube 191 and to a grounding contact 193,which cooperates with the switch 148. Arm 146, which is grounded, alsoengages stationary contact 143 in its deenergized position, which lateris connected to contact 124 by line 141. The plate of tube 191 isdirectly connected to relay 142.

In the operation of the tuner, let it be assumed that the parts are inthe position shown and the set deenergized. Switch 151 is first closed.This completes an obvious circuit through solenoid coil 62 to energizethe same and cause the carriage to move to the opposite extremity. VAsitapproaches this position, arm 138 engages switch arm 126 to move it tothe right as shown in Figure l0, breaking its contact with switch point124 to deenergize the coil 62, and moving it into engagement with lswitch point 128, which merely acts as a stop. At this point, the`spring 60 is now in condition to drive through the series of gears andthe governor load, but it can not do so since arm 144 engages the end ofthe y governor to restrain itl from movement, being held there by thetension of the spring 152. At this point arm 146 is biased out ofengagement with the y governor by spring 150, and would permit it torotate and the carriage to move to cause a scanning of the bandelectrically.

After a short period of time to permit the various tubes to warm up, theoperator may force in switch 148, which is simply a grounding switch,but in this instance it completes a circuit through the coil 140 andthis coil, therefore, attracts its armature to disengage the arm 144from the governor and the spring begins to drive the carriage slowlyacross the tuner. At the same time a holding-circuit is completedthrough the relay 140 by engagement between the arm 144 and stationarycontact 145. This will maintain the arm 144 out of engagement with thegovernor until such time as the set is next turned off, the main purposeof this arm being to keep the tuner in the position it last held, priorto turning oli the main switch. If the tubes have not as yet warmed upsutiiciently to pass an adequate signal, the tuner will merely keepscanning the band until such period of time has passed.

Tube 167Y is designed to normally pass current when the tuner is workingor scanning the band, and since current would flow in its plate circuitif it were conducting, this-places a bias on the grid 189 of the tube191 through potential drop across resistor 181 and tube 191 would,`under these conditions, be non-conductive. However, as soon as a signalof suicent strength applies a `potential on line 161, it overcomes thepotential on the grid 165 and causes this tube to become non-conductive,at which instantv the bias will be removed from the grid 189 and tube191 will conduct. Relay 142 is now energized and will pull arm 146 intoengagementwith the -y governor 114, and stop the tuner on station. Thisalso breaks the grounding circuit for relay 62 so that that relay cannotbecome energized as long as relay 142 acts as a track therefor.

remains energized. Itwillreman*energized until ktheoperator-isfdesirousof obtaining another station, at which time,` byclosing switchl148,1the 'tube 191 is shunted 'to cause relay 142 to"drop-out and close a shorting contact on the condenserA 179. 4The tubesgo back to their tprior described condition, coil 140 is v:energized toremove the arm V144 from engagement with the governor 114, and the tuneragain scans,"ntil -affurther station signal causes them to again stop onstat-ion.

The modified form of vour invention shown in Figures 11 through 17inclusive voperateson'the same general principles as the form justldescribed. In this form there is provided a casing 160 within whichtaremounted a plurality of tuningcoils 2 into whichthe series of comminutedcores 4 are'plunged to tune` the receiver. 'The cores are,'as in theprevious instance', mounted in adjustable spaced parallel relation onatransverse bar 6, `Which is rigidly secured to a vlongitudinally movable`carriage guided, las previously, by a tie rod 20 which An internalframe platform 170 has an actuating solenoid 162 mounted thereon whoseplunger or armature `164 is pivotally connected to one end of a largesector gear 166 by a link 164. This gear is itself pivotally mounted at168 on the plat- `form 170 and has av series of teeth 172 in its outerarcuate edge. p

The platform carriesla stub shaft 174 rigidly thereon adjacent the outeredge of the sector gear. j This stub `shaft is provided with sections ofdiffering diameter and the outer` end -is threaded. A large spur gear176 is rotatably mounted on this shaft'and has rigidly Vaffixed to oneside thereof a circular toothed member 178 which forms one-half of'ayone-way or overrunning jaw clutch. A second toothed member 180, havingteeth on the side adapted to engage the teeth on the member "178, saidassociated teeth being so tapered that they will provide va drive frommember 180 to member 178 in'o'n'e direction but will slip over theassociated teeth when lrotated in the opposite direction, is mounted onthe next section of the shaft 174. A pinion `182 is likewise mounted onthe shaft next in order and is rigidly secured to rotate with the clutchmember 180. A concentric spring member 184 bears against theupper endofthe pinion gear 182 tending to force it axially downward on the's'haft174 as shown in Figure 1l, and is retained-in compressed condition bylocking nuts 186, which are threaded on to the outer end of the shaftr1774. The-compressed spring :184 tends to keep the clutch members 180andV 178 vsecured to a spur gear 192 to rotate therewith. The

pinion engages the spur gear 176 and the associated spur gear 192 drivesasecond pinion 194 mounted on a short drive shaft 196, which issupported'in `a bearing 198 also carried by the plate 170. On theopposite side of the plate 170 from the pinion 194 there is mounted onthis shaft 196 a ratchet gear 200, which acts as the indexing 'stopmember havingI a pawl or indexing member 202 Vwhich is so mounted as tocontact the periphery of the wheel 200 for indexing purposes. The pawlarm 202 is pivotally mounted on a framemember 204 and actuated :by Varelay coil 206, supported on a bracket from the frame member 170'. Aspringmember 208 tends to maintain the pawl arm v202 in ycontact withthe indexing `Wheel 200i, but the pawl arm is withdrawn from contactwith the wheel 200 by energization of the relay coil 206.

From the aboveit will be obvious that the sector gear is 'rotated aboutits pivot 168 in one direction by the solerioid 162'whentheilatterinductively sucks its armature inwardly. This sector plate ismoved in the op- 8 posite direction about `itspivot Vby a coil spring210, which has'onefendV engaging one-'of a series 'of openings 212 inthe edge of the's'ector gear,`"the Vother end of said spring'beingattached to 'a frame member as at 214. By moving the end of the springmember 210 to different radially spaced openings in the side of thesector gear, the amount of spring tension for driving the same may bevaried. 'The sector gear 166 may, therefore, be rotated in one directionabout its pivot by action of the solenoid and in the opposite directionby action of the spring 210. y

In order to provide a drive means from the sector gear to the carriage10 a pin 214 is driven into the side of the sector gear adjacent-thetoothed end, said pin being 'connected by a link system 216 with thecarriage it?, and as the sector gear rotatesback and'forth the carriagewill be moved longitudinally toits two desired limits. A reversingswitch assembly-218 is provided and two fixed actuatin'g'membeis 220 and-222 engage the snap-over switch arm 224 yof the'reversing switch atopposite e'nds of the track. A similar pointer or indicator assembly 226is shown 'for indicating the position of the tuning mechanism.

In the circuit diagram shown on Figure 17 for this form of ourinvention, there-is provided a battery 230. A switch 231 and conductiveline V232 are connected to tlievbattery and to the solenoid coil 162 andthence to the reversing switch arm 224. Clie of-V the stationarycontacts 225 which the switch arm 224 engages is grounded through line227 and contact 229 with which the grounded arm 202 engages when coilV206 is'energized. A conductive line 234 extends from switch-231 to thecathodes of each of the tubes 236, 238, and 240. Relay v206 is Vdirectlyconnected tothe plate 242 of tube 240 and is energized when this tubeconducts. In this case, however, the index Wheel is locked or indexedwhen the 'relay is deenergized and continues to run when relay 206 isenergized. The incoming signal developed is applied to line 244 andthrough resistor 246 to control grid 248 of tube 240.

The armature 202 also carries a movable arm 250, which engages a switchcontact 252 connected through resistor 254 to grid 256 of tube 240. Arm250 is cong nected through line 258 to the B battery line 260.Conductive line 262, which extends from plate 242 to relay 206 is tappedand connected byline 266r through resistance 268 and Aswitch A270 toground.

In the operation of this rnodication, the main switch 231 isvrst closedto warm up the tubes and place the equipment in operative, condition.The'arm 202 engages the teeth on the wheel 200 due to spring bias andthat is locked.

When 'a sufcient length of time has elapsed to place the tubes' inoperative condition, switch 270 is closed momentarily to complete'anobvious circuit for relay coil 206, which attracts its armature andpermits the wheel 200 to turn and throughr the gear train load thesector gear so that it slowly rotates about its 4pivot and moves thetuning carriage along its path to scan the band. It

also completes the circuit for solenoid `162 through grounding contactl22.9, and, when arm 222 throws arm 224 tothe position shown in Figure17, which is of course at one extremity of travel, the solenoidoperation immediately moves the sector gear to the other extremity ofits `movement tol cock the driving spring. Simultaneously with theremoval of the stop 262, the movement of the armature closes switch 252,which applies a biasing rpotential to grid 256 of control tube 248. Ifthe tube has had a suicient time to warm.- up, it now conducts and relayv206 remains energized and thespring drive will scan 'the band.

Upon the receipt Vofv a signal ofM suicient strength to `act'uate thecontrol "system, depending on its setting, a negative voltage w'illbeapplied to gridl 248 to cut off the iflowin the tube' and relay 206'wi1ldrop its armature: to -lo'ck thewheel 200 yand indexy the tuner.

If that station is not desired, the operator momentarily closes switch270 again, which energizes relay 206 directly, and starts the drivetoward the next station.

There is no manual drive provided with this form of our invention, butif the operator desires to move a large distance across the band to adesired station, he may hold the switch 270 in until the approximatelocation of the desired station is reached, and the tuner will proceedin uninterrupted motion until the switch 270 is released and then "thenext incoming signal will stop it.

We claim:

l. In radio receiving means, movable tuning means for tuning thereceiver over a predetermined band of frequencies, electro-mechanicaldriving means, energy transferring means interconnecting theelectro-mechanical driving means and the movable tuning means and havinga plurality of force reaction points about which parts of the energytransferring means may move to move said movable tuning means, relayactuated means operatively engageable with the `energy transferringmeans to index the movable tuning means upon receipt of an incomingsignal and to provide a force reaction point in the energy transfermeans and manually operable means engageable with a different point inthe energy transferring means to drive the same to move the energytransferring means about the force reaction point provided by the relayactuated means when that has indexed upon a particular station.

2. In radio receiving means, movable tuning means for tuning thereceiver over a predetermined band of frequencies, energy transferringmeans connected to said movable tuning means and having a plurality offorce reaction points about any of which the energy transferring meansmay move to move said movable tuning means, electro-mechanical drivingmeans operatively connected to said energy transferring means to movethe latter about one force reaction point and tune the receiver andmanually adjustable means operatively connected to said energytransferring means to move the same about another force reaction pointand also tune the receiver.

3. In radio receiving apparatus, a frame, a carriage reciprocablymounted on said frame, means for tuning said radio apparatus over apredetermined band of frequency mounted on said carriage, automaticallycontrolled driving means for moving said carriage in both directions,force transmitting means connected to said driving means and having aplurality of interconnected parts sequentially transmitting force,indexing stopping means engageable with a part of the force transmittingmeans to engage and lock the same upon the receipt of an incoming signalin the apparatus and manually operated means operatively connected toanother part of the force transmitting means to drive the carriage whilethe part first mentioned is prevented from moving due to the engagementof the indexing stopping means.

4. In mechanism for moving a carriage in opposite directions over apredetermined path, power meansconnected thereto to drive it in eitherdirection between prescribed limits, a multiplying gear train connectedto the carriage to be driven by movement of the same, indexing meansengageable with the gear on the opposite end of `the train from thatconnected to the carriage to index and lock the same to stop carriagemovement at desired points and manually actuatable means connected tothe gear train to drive the carriage when the gear train is locked.

5. In mechanism for moving a carriage in opposite direc-tions over apredetermined path, resilient means to drive the carriage in onedirection connected to said carriage, solenoid means connected to saidcarriage for moving it in the opposite direction, a gear train connectedto said carriage and driven by movement of the same, a governorconnected to the opposite end of the gear train to provide a dampingeffect and slow down the speed of travel induced by theresilient drive,ratchet means in said gear train to provide drive in the direction oftravel induced by the resilient bias but rotate freely in the directionof solenoid drive to remove the gear load when the solenoid is loadingthe resilient means, index means engageable with the governor to lockthe same at desired positions, and manually rotatable means engagingsaid gear train to provide a reaction point when the resilient drive isoperating and to drive the carriage when the gear train is locked by theindexed means.

6. In mechanism for moving a carriage lin opposite directions over apredetermined path, resilient means to drive the carriage in onedirection connected to said carriage, solenoid means connected to saidcarriage for moving it in the opposite direction, a gear train connectedto said carriage and driven by movement of the same, a governorconnected to the opposite end of the gear train to provide a dampingeffect and slow down the speed of travel induced by the resilient drive,ratchet means in said gear train to provide drive in the direction oftravel induced by the resilient bias but rotate freely in the directionof solenoid drive to remove the gear load when the solenoid is loadingthe resilient means, index means engageable with the governor to lockthe same at desired positions, manually rotatable means engaging saidgear train to provide a reaction point when the resilient drive isoperating and to drive the carriage when the gear train is locked by theindex means, said gear engaged by the manually rotatable means beingfrictionally mounted so that continued movement of the manual meansafter the carriage has reached one limit of movement will cause the gearto slip and prevent damage to the device.

7. In a mechanism for moving tuning elements of a radio receiver havinga member movable between prescribed limits over a given path connectedto said tuning elements, a pivotallyrmounted framework connected to saidmember to move the same by its rotation about its pivot, driving meansconnected to said framework to move it in opposite directions, a shaftin said framework, a first gear frictionally mounted on said shaft, asecond gear freely mounted on said shaft, a pawl and ratchet connectionbetween said second gear and the shaft, a gear train engaging saidsecond gear and means engaging `said first gear so that the gear trainwill be driven by the second gear as the framework revolves and movesthe tuning means, said gear train acting as a damping load for thismovement.

8. In a mechanism for moving tuning elements of a radio receiver havinga member movable between prescribed limits over a given path connectedto said tuning elements, a pivotally mounted framework connected to saidmember to move the same by its rotation, driving means connected to saidframework to move it in opposite directions, a shaft in said framework,a tirst gear frictionally 'mounted on said shaft, a second gear freelymounted on said shaft, a pawl and ratchet connection between said secondgear and the shaft, a gear train engaging said second gear and manuallymovable means meshing with said first gear to act as a reaction pointand cause said shaft to turn in said second gear to drive the gear trainwhen the framework moves around its pivot due to the driving means.

9. In a mechanism for moving tuning elements of a radio receiver havinga member movable between prescribed limits over a given path connectedto said tuning elements, a pivotally mounted framework connected to saidmember to move the same by its rotation, driving means connected to saidframework to move it in opposite directions, a shaft in said framework,a rst gear frictionally mounted on said shaft, a second gear freelymounted on said shaft, a pawl and ratchet connection between said secondgear and the shaft, a gear train lengaging said second gear, manuallymovable means meshing with said rst gear to act as a reaction point vand'cause 'said shaftr `to turn in said 'second gear to drive the vgear`train kwhen theframe'work moves around its pivot due to the drivingmeans, llocking -means engageable with the 'most remote'fgear of thefgear train to stop the framework at desired positions said manuallymovable means driving said framework when said gear train is locked andsaid first gear overcoming itsfri'ctional mounting Iif continuedmovement of said manually 'movable 'means continues after'the frameworkhas reached a limit of movement.

1'0. In 'indexing means, a casing, 'a carriage movably mounted on saidcasing, a 'solenoid connected to said carriage to move the latter in onedirection upon lenergization, spring biasing mea-ns vconnected to saidcarriage 'to move the latter in-the opposite direction, a gear train"connected to said carriage to be rotated by movement of 'the same, aportion of said gear train being of the planetary type-and manuallyrotatable means mounted to engage the gear train kso that the ycarriagemay be moved in one direction by the solenoid, in the opposite directionby the spring or in either direction by the manual drive.

ll. In indexing means, a casing, a carriage movably 'mounted on saidcasing, a solenoid connected to said 'carriage to move the latter'in onedirection upon energi'zation, spring biasing means connected to saidcarriage to move the latter in the opposite direction, a gear vtrainconnected t`o said carriage to be rotated by lmovement of the same, agovernor connected to the lend 'of the gear train to dampen the rotationand control the movement of the carriage when under spring drive, aportion of the gear train being planetary and manually rotatable meansconnected to the gearing to drive the carriage.

l2. In radio apparatus, a casing, a carriage mounted for'reciproc'atorymotion on said casing, means for tuning said radio apparatus over apredetermined frequency band mounted on said carriage, a pivotallymounted framework, link means interconnecting said carriage andframework to cause reciprocation of the carriage as the frameworkrotates, a train of gearing carried by the casing, manually rotatedmeans mounted on the casing and meshing with the gear train andplanetary gearing mounted in the framework and in mesh with the geartrain to cause 'rotationjof the framework and drive the carriage uponthe operation ofthe manually rotated means.

13. In radio apparatus, a casing, a carriage mounted for'reciprocato'r'y motion on said casing, means for tuning said f radioapparatusl overa predetermined frequency band mounted on said carriage,-a pivotally mounted framework, link means interconnecting said carriageand framework to cause recipr'cation of the carriage as the frameworkrotates, a train of gearing carried by the casing, manually rotatedmeans mounted on the casing and said radio apparatus over apredetermined frequency band mounted on said carriage, a pivotallymounted framework, link means interconnecting said carriage andframework to canse'reciprocation of the carriage as the framev'vorkrotates, atrain of gearing carried by the casing-,manually rotated meansmounted on the casing and 'meshing with the gear train, planetarygearing mounted in the framework andin mesh with the gear train to causerotation of the framework and drive the carriage upon the operation ofthe-manually rotated means, solenoid means connected to said frameworkto lrotate itin one direction upon energization', spring biasing meansconnected to the frameworkrto rotate it in the Opposite direction whenthe solenoid i's 'deenergized, y governor means connected to 'the -geartra'in to control the rotation thereof, pivotall stop means in the`casing to engage the governor and relay means for actuating the stopupon signal from the set to vindex the apparatus.

15. In radio apparatus, a casing, a carriage mounted for re'ciprocatorymotion on said casing, means for tuning said radio apparatus Vover apredetermined frequency band mounted on` said carriage, a pivotallymounted framework, link means interconnecting said carriage andframework to cause reciprocation of the carriage as the frameworkrotates, a train of reduction gearing carried by 'the casing, 'manually4Irotatedmeans mounted on the casing -and meshing with they gear train,planetary gearing mounted in the framework and in mesh with the geartrain to cause rotation of the framework and drive the carriage uponVthe operation of the manually rotated means, solenoid `means connectedto said framework to rotate it in one direction upon energization,'spring biasing means connected to the framework to rotate it in theopposite direction when the solenoid is deenergized, reversing switchingmeansr mounted on the casing and connected to the solenoid andswitchop'erating stops mounted in spaced relation on the carriage tothrow the reversing switchat the extreme ends of travel of the carriage.

16. In radio apparatus, a frame, a `carriage reciproeably mounted onsaid frame, means for tuning said radio apparatus o` ve'r apredetermined vband of frequency mountedv on said carriage,automatically controlled driving means for moving saidcarriage in bothdirections, a planetary gear system connected tothe driving means andmanually controlled means connected to the gear system so that thecarriage maybe moved either automatically or manually. t

17. In radio apparatus, a frame, a carriage reciprocably mounted on saidframe, means for tuning said radio apparatus over a predetermined bandof frequencies mounted on said carriage, automatically controlleddriving means for moving the carriage in both directions, a planetarygear system connected to the driving means, manually controlled meansconnected to the gear system eo that the carriage l'may be moved Veitherautomatically 'or manually and friction driving means in the gear systemwhich mayv slip and provide protection for the parts if the manual meansis continued to be rotated after the carriage Vreaches a limit ofmovement.

4 18. In radio apparatus', a casing, a carriage mounted forreciprocatory motion on said casing, means for tuning said radioapparatus over a predetermined frequency band mounted 4on vsaidcarriage, a pivotally mounted framework, link means interconnecting saidcarriage and said framework to cause reciprocation of the carriage asthe framework rotates, a train of gearing carried by the casing,manually rotated means mounted on the casing and meshing with the geartrain, planetary gearing mounted in the framework and in mesh vwith thegear train to cause rotation of the framework and drive the carriageupon the operation of the manually rotated means and friction drivingmeans `in the planetary vgearingwhich may slip andv provide protectionif movement of said manually rotated means continues after said carriagehas reached a limit of movement.

19. In radio apparatus, a frame, a carriage mounted for reciprocatorymovement on said frame, solenoid means connected to the carriage to moveit in one direction upon energization, spring biasing means connected tothe carriageto movel itin the opposite direction to that of thesolenoid, reduction gear train connected to the carriage to bey rotatedby` movement of the latter, a fly governor driven by the gear train, aplurality of pivoted stop members engageable with said governor tocontrol rotation thereof, spring biasing means4 to tendk to maintain onestop`v in engagement' with the governor to block the 13 same and to tendto 'maintain another stop means out' of engagement, relay means formoving the first-mentioned stop means out of engagement with thegovernor, energizing means for the same operative at all times when theapparatus is in use, and relay means to move the second stop memberVinto engagement with the governor when a voltage is generated in theapparatus upon transmitted signals being received to cause the drive tostop.

1,968,302 Maurer July 31, 1934 14 Knos et al. June 18, 1940 Muller July9, 1940 Wandrey Feb. 9, 1943 Andrews Aug. 17, 1943 Andrews Ian. 10, 1950Gierwiatowski Jan. 10, 1950 Dunn Mar. 7, 1950 Goodrick June 13, 1950Carlzen June 27, 1950 Jackson Nov. 7, 1950 Andrews Feb. 13, 1951

